Electromagnetic shielding sleeve for protecting bundles of cables and methods of construction thereof and protecting wires therewith

ABSTRACT

A tubular electromagnetic shielding sleeve has a longitudinal slit. The inventive sleeve includes a substrate ( 11 ) and a layer ( 12 ) of electrically-conductive material which is fixed to the inner face of the substrate ( 11 ), the layer ( 12 ) extending essentially from one edge ( 11   a ) to the other longitudinal edge ( 11   b ) of the substrate ( 11 ). Moreover, the substrate ( 11 ) and the layer ( 12 ) are separated from one another along a split segment ( 13 ) on at least one first longitudinal edge ( 11   a ). The invention can be used, for example, to protect bundles of electric cables ( 14 ) for use in aeronautics.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of prior U.S. application Ser. No.10/550,727, filed Sep. 26, 2005, which was the National Stage ofInternational Application No. PCT/FR04/00695, filed Mar. 22, 2004, whichclaims the benefit of French Application No. FR03/03552, filed Mar. 24,2003, all of which are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to textile sleeves used to protect bundlesof electrical cables, and more particularly to textile sleeves and theirmethods of construction and use for providing electromagnetic protectionto electric wires or cables.

2. Related Art

The present invention applies generally to protecting wires, cables orbundles of wires by electromagnetically shielding them in order toprotect them from electromagnetic interference and radio-frequencyinterference.

This type of electromagnetic protection is routinely used in theautomotive, rail cabling and aeronautical fields.

Electromagnetic interference protection standards are drawn up for eachfield of application and may require protection of the order of 40 to 45dB in the automotive field or of the order of 80 to 90 dB in theaeronautical field.

Self-closing sleeves of polyester fabric coated with copper or nickelfor providing electromagnetic protection are known in the automotivefield, for example.

Electrical continuity is provided by an overlap on the outside face ofthe textile sleeve, where a folded longitudinal edge producescopper-to-copper contact.

A protective sleeve of the above kind is described in the document EP 1175 683 in particular.

However, this kind of sleeve can offer only low protection tointerference and is therefore difficult to transpose to the aeronauticalfield.

In the aeronautical field, maximum efficiency in terms ofelectromagnetic shielding is obtained by using copper wires, for examplein the form of a copper braid.

In the conventional way, copper wires are overbraided around the cableto be protected, for example with a coverage rate of around 75%. Thecoverage rates required in the aeronautical field are frequently inexcess of 90%.

A layer overbraided with textile filaments may be added to providemechanical protection of the bundle of cables and the copper shielding.

However, the above shielding is difficult to fit to a bundle of cables.

Moreover, it is particularly difficult, or even impossible, to maintainand replace shielding and mechanical protection elements if the bundlesof cables are installed and connected in their operationalconfiguration.

SUMMARY OF THE INVENTION

An object of the present invention is to eliminate the problems citedabove and to propose an electromagnetic shielding sleeve providingefficient shielding at lower cost, in particular in the aeronauticalfield.

To this end, the present invention is directed to a longitudinally slittubular electromagnetic shielding sleeve comprising a substrate and anelectrically conductive material layer fixed to an internal face of thesubstrate, the layer extending substantially from one longitudinal edgeof the substrate to the other longitudinal edge thereof.

According to one aspect of the invention, the substrate and theelectrically conductive material layer are separated in a split segmentat one first longitudinal edge at least.

This split segment thus forms a housing adapted to receive the secondlongitudinal edge of the substrate, so that electrical continuity can beproduced in the layer of electrically conductive material that is fixedfrom one edge of the substrate to the other edge thereof.

Thanks to this split segment, electrical continuity may be producedinside the sleeve, so that this area of electrical contact is protectedby the first longitudinal edge of the substrate on the outside face ofthe sleeve.

Furthermore, thanks to the longitudinally slit substrate, it is easy tofit and in particular to replace a worn out sleeve, even if the bundlesof cables are positioned for their final application. This facilitatesmaintenance and retro-fit operations.

In a preferred embodiment of the invention, the electrically conductivematerial layer is formed of an interleaved copper wire structure,providing a high density of copper to assure efficient shielding of thebundles of cables.

A braided copper wire structure produces a high rate of coverage by theelectrically conductive material around the cables to be protected.

According to another preferred feature of the invention, the substrateis produced in the form of a sheet thermoformed into a self-curlingstrip with an overlap.

Thus the shape of the substrate greatly facilitates fitting the sleevewith an overlap producing electrical continuity in the split segment ofthe sleeve.

Thus the second longitudinal edge of the sleeve is adapted to beinserted between the substrate and the electrically conductive materiallayer in the split segment.

This sleeve is particularly suitable for protecting bundles ofelectrical cables in the aeronautical field, but may also be used in theautomotive and rail sectors.

Further features and advantages of the invention will become apparent inthe course of the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the appended drawings, which are provided by way of non-limitingexample:

FIG. 1 is a perspective view of an electromagnetic shielding sleeve ofthe invention;

FIG. 2 is a view of a first embodiment of an electromagnetic shieldingsleeve of the invention;

FIG. 3 is a view in cross section of the first embodiment of anelectromagnetic shielding sleeve of the invention fitted around a bundleof cables;

FIG. 4 is an end view of a second embodiment of an electromagneticshielding sleeve of the invention; and

FIG. 5 is a view in cross section of the second embodiment of anelectromagnetic shielding sleeve of the invention fitted around a bundleof cables.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

The general principle of an electromagnetic shielding sleeve of theinvention is described first with reference to FIG. 1.

The general shape of the sleeve 10 is that of a slit tube.

In the present example the sleeve more particularly comprises asubstrate 11 adapted to curl up on itself to form a longitudinally slittube.

This substrate is preferably produced from a plane strip in the form ofa thermoformed sheet. The thermoforming operation converts the flatstrip into a self-curling strip with an overlap, the longitudinal edges10 a, 10 b of the sleeve being adapted to come into contact with eachother in an overlap portion.

The substrate is preferably a woven textile strip. The textile filamentsmay be polyester monofilaments and/or multifilaments, for example.

For example, polyphenylene sulfide (PPS) filaments may be used.

Alternatively, a substrate may be produced from NOMEX® from du Pont deNemours.

The NOMEX® or PPS substrate provides effective mechanical protection ofthe cables to be protected.

A NOMEX® substrate has the additional advantage of good fire resistance.

According to the invention, this textile substrate 11 is associated withan electrically conductive material layer 12.

The layer 12 is preferably formed from braided copper wires.

Tinned or nickel-plated copper wires may be used, and copper wires witha diameter from 0.10 mm to 0.25 mm, and preferably from 0.12 mm to 0.15mm, can be braided to form an elongate strip of conductive material.

The braiding technique produces a strip in which the rate of coverage bythe copper is of the order of 92% of the total area of the strip.

This copper layer 12 is fixed to an internal face 11 c of the substrateso as to extend from one longitudinal edge 11 a of the substrate 11 tothe other longitudinal edge 11 b thereof.

As clearly shown in FIG. 1, this conductive material layer may extendover only a limited longitudinal portion of the sleeve 10.

Of course, this layer 12 may equally extend over the whole of the lengthof the sleeve 10.

As clearly shown in FIG. 2, in a first embodiment, the substrate 11 andthe layer 12 are separated in a split segment 13 along a firstlongitudinal edge 11 a of the substrate 11.

Accordingly, in this split segment 13, the second longitudinal edge 10 bof the sleeve may be inserted between the substrate 11 and the layer 12.

The split segment 13 subtends an angle α that is sufficient to allowsufficient insertion of the second longitudinal edge 10 b into thissplit segment 13.

The angle a may be substantially equal to 90°, for example.

As shown clearly in FIG. 3, when this sleeve 10 is fitted around abundle of cables 14, the second longitudinal edge 10 b of the sleeve 10is inserted between the layer 12 of conductive material and thesubstrate, more particularly the first longitudinal edge 11 a of thesubstrate, so that electrical continuity may be obtained in the layer12, thanks to contact between the longitudinal edges 12 a, 12 b of thecopper layer 12.

Thus there exists an overlap portion 15 in which one longitudinal edge10 a of the sleeve 10 overlaps the other longitudinal edge 10 b thereof.This overlap portion 15 subtends an angle α from 60° to 90° with respectto the longitudinal axis of the tubular substrate 11.

This overlap portion 15 is larger or smaller according to the diameterof the bundles of cables 14 to be protected, what is important being tohave good contact between the two longitudinal edges.

A second embodiment of the electromagnetic shielding sleeve of, theinvention is described next with reference to FIGS. 4 and 5.

In this embodiment, the substrate 11 and the electrically conductivematerial layer 12 are separated in two split segments 13 and 13′, one ofthese split segments 13 being adjacent to the first longitudinal edge 10a of the sleeve 10 and the other split segment 13′ being adjacent to thesecond longitudinal edge 10 b of the sleeve.

Accordingly, as shown clearly in FIG. 5, these split segments 13, 13′are adapted to be interleaved in an overlap portion 15′ so that theedges 12 a, 12 b of the conductive layer come into contact with eachother inside the sleeve and the longitudinal edges 11 a, 11 b of thesubstrate come into contact with each other outside the sleeve.

Accordingly, in both embodiments described above, electrical continuityof the conductive material layer 12 is produced inside the sleeve 10,the substrate 11 covering this contact portion to maintain theelectrical connection mechanically.

Reliable and efficient shielding is thus obtained, suitable for bundlesof aeronautical cables.

This electromagnetic shielding sleeve may be fabricated by sewing theelectrically conductive material layer 12 to the substrate 11 by meansof one or more rows of stitches 16, 16′, 16″ extending in thelongitudinal direction of the sleeve 10, for example.

At least one of the rows of stitches 16′ is sufficiently far from onelongitudinal edge 10 a of the sleeve to allow separation of thesubstrate and the layer 12 in the vicinity of that longitudinal edge.

If the substrate is a thermoformed textile woven strip, the copper braidis fixed to the textile woven strip by lines of stitches before thethermoforming step.

Alternatively, this sleeve could be produced by a tube weaving process,one layer being made of copper wires and one layer being made of textilefilaments. A double weaving process of this kind would eliminate theoperation of fixing the copper layer to the textile filament layerduring fabrication of the sleeve.

The electromagnetic shielding sleeve of the invention therefore achievesefficient shielding and is simple to use around bundles of cables to beprotected, even if the latter are installed in an engine and connectedup, for example.

Of course, many modifications may be made to the embodiment describedabove without departing from the scope of the invention.

In particular, in the second embodiment, in which a split segment isprovided at both longitudinal edges of the sleeve, one of thelongitudinal edges, comprising both the substrate and the electricallyconductive material layer, may be inserted integrally between thesubstrate and the conductive material layer of the other longitudinaledge.

Moreover, the edges 12 a, 12 b of the electrically conductive materiallayer 12 may extend more or less as far as the longitudinal edges 11 a,11 b of the substrate 11 if it suffices to produce a small area ofoverlap of the two edges 12 a, 12 b of the electrically conductivematerial to provide electrical continuity.

Furthermore, the tubular sleeve could be formed, instead of from aself-curling strip, from a plain strip adapted to be curled up around abundle of cables and held in that position by fixing means such as cableties or rings distributed along the length of the sleeve.

Moreover, the substrate may be formed of a knitted or braided textilestrip.

Similarly, the conductive material layer may be made from woven copperwires.

1. A wrappable sleeve for protecting elongate members, comprising: anon-conductive substrate having an outer face and an inner faceextending between opposite longitudinally extending edges overlappingone another along a length of said sleeve to provide a wrappedsubstrate; and a metallic layer attached to said inner face of saidsubstrate and having opposite unfolded longitudinally extending edgeregions brought together to provide a circumferentially continuous metalshield within said wrapped substrate.
 2. The wrappable elongate sleeveof claim 1 wherein said opposite unfolded edge regions overlap oneanother.
 3. The wrappable elongate sleeve of claim 1 wherein saidsubstrate is biased to self curl.
 4. The wrappable elongate sleeve ofclaim 1 wherein said unfolded longitudinal edge regions extend toopposite free edges that face in opposite directions from one another.5. The wrappable elongate sleeve of claim 1 wherein said unfoldedlongitudinal edge regions remain in abutment with said inner face ofsaid non-conductive substrate.
 6. A wrappable sleeve for protectingelongate members, comprising: a non-conductive textile substrate havingan outer face and an inner face extending between opposite edgesdefining a width of said substrate and overlapping one another along alength of said sleeve to provide protection to the elongate members; anda metallic layer attached to said inner face of said substrate andhaving opposite free edges extending along the length of said sleeve andbeing brought together to provide an uninterrupted metal shield, saidfree edges defining a width of said metallic layer, said width of saidnon-conductive layer being no greater than said width of said metalliclayer.
 7. The wrappable sleeve of claim 6 wherein said metallic layer isattached to said substrate by at least one row of stitches.
 8. Awrappable sleeve for protecting elongate members, comprising: anon-conductive textile substrate having an outer face and an inner faceextending between opposite longitudinal edges, said substrate providingcircumferentially continuous protection to the elongate members; and ametallic layer of interlaced wires having opposite free edges extendingalong a length of said sleeve, said free edges being arranged to overlapone another to provide a circumferentially continuous metal shield, saidmetallic layer being attached to said substrate by at least one row ofstitches extending along at least one of said free edges and adjacentone of said longitudinal edges of said substrate.
 9. The wrappablesleeve of claim 8 wherein one row of stitches extends along one of saidfree edges of said metallic layer adjacent one of said longitudinaledges of said substrate and another row of stitches extends along theother of said free edges of said metallic layer adjacent the other ofsaid longitudinal edges of said substrate.
 10. The wrappable sleeve ofclaim 8 wherein said opposite longitudinal edges overlap one another toprovide an overlap portion, said overlap portion extending up to 90degrees circumferentially about said sleeve.
 11. The wrappable sleeve ofclaim 8 wherein said free edges of said metallic layer overlap oneanother to provide an overlap portion, said overlap portion extending upto 90 degrees circumferentially about said sleeve.
 12. The wrappablesleeve of claim 8 wherein said textile substrate is woven at least inpart from monofilaments.
 13. The wrappable sleeve of claim 12 whereinsaid monofilaments are polyester.
 14. The wrappable sleeve of claim 12wherein said textile substrate is thermoformed into a self-curlingfabric.
 15. The wrappable sleeve of claim 12 wherein said textilesubstrate is woven at least in part from multifilaments.
 16. Thewrappable sleeve of claim 8 wherein said interlaced wires are braided.17. The wrappable sleeve of claim 16 wherein said wires are at least inpart copper.
 18. A wrappable sleeve for protecting elongate members,comprising: a woven substrate having an outer face and an inner face,said outer face providing circumferentially continuous protection to theelongate members; a metallic layer of interlaced wires having oppositefree edges arranged to overlap one another to provide acircumferentially continuous metal shield about the elongate members;and a row of stitches extending adjacent one of said free edges andattaching said metallic layer to said inner face of said substrate. 19.The wrappable sleeve of claim 18 further comprising another row ofstitches extending adjacent the other of said free edges.
 20. Thewrappable sleeve of claim 18 wherein at least one of said free edges ofsaid metallic layer is spaced from said substrate.
 21. The wrappablesleeve of claim 18 wherein said substrate has opposite longitudinaledges extending along a length of said sleeve and defining a width ofsaid substrate and said free edges of said metallic layer defining awidth of said metallic layer, said width of said metallic layer being atleast as great as said width of said substrate.
 22. A wrappable sleevefor protecting elongate members, comprising: a woven substrate having anouter face and an inner face extending between opposite longitudinaledges extending along a length of said sleeve and defining a width ofsaid substrate, said inner face adjacent one of said longitudinal edgesbeing arranged to overlap said outer face adjacent the other of saidlongitudinal edges to provide circumferentially continuous protection tothe elongate members; a metallic layer of interlaced wires havingopposite free edges defining a width of said metallic layer, said freeedges being arranged to overlap one another to provide acircumferentially continuous metal shield about the elongate members;and wherein said width of said metallic layer is at least as great assaid width of said substrate.
 23. The wrappable sleeve of claim 22further comprising at least one row of stitches attaching said metalliclayer to said inner face of said substrate.
 24. A method of constructinga wrappable sleeve for providing electromagnetic protection to wires,comprising: forming a non-conductive textile substrate having an outerface and an inner face extending between opposite edges defining a widthof said substrate; interlacing wires to form a metallic layer havingopposite free edges defining a width of said metallic layer, said widthof said substrate being no greater than said width of said metalliclayer; and attaching said metallic layer to said inner face of saidsubstrate so that said opposite free edges of said metallic layer arearranged to overlap one another.
 25. The method of claim 24 furtherincluding thermoforming said substrate after the attaching the metalliclayer to the substrate.
 26. A method of protecting wires againstelectromagnetic interference in a wrappable textile sleeve, saidwrappable textile sleeve having a non-conductive textile substrate withan outer face and an inner face extending between opposite edgesextending along a length of the sleeve and a metallic layer attached tothe inner face of the substrate and having opposite edge regions, themethod comprising: wrapping the substrate and the metallic layer aboutthe wires and bringing the opposite edges of the substrate intooverlapping arrangement with one another and bringing the edge regionsof the metallic layer into overlapping contact with one another with theover lapping edge regions remaining in a generally flat and an unfoldedconfiguration.